1. Field of the Invention
The present invention relates to semiconductor devices, and more particularly to composite unipolar-bipolar semiconductor devices.
2. Description of the Prior Art
Composite unipolar-bipolar semiconductor devices are found in the prior art. Some of these prior art devices consist merely of electrically isolated field-effect transistors and bipolar junction transistors, which for compactness or ease of fabrication constitute parts of the same unitary semiconductor structure. Other ones of such prior art devices consist of field-effect transistors and bipolar junction transistors which, rather than being mutually completely isolated, are interconnected through portions of the same unitary semiconductor structures of which they are parts. Further, it is known in the prior art to provide composite unipolar-bipolar semiconductor devices the major elements of which are symmetrical about a common axis. In general, however, the composite unipolar-bipolar semiconductor devices of the prior art can be represented by equivalent circuits made up of one or more field-effect transistors and one or more bipolar junction transistors, interconnected or isolated. For this reason, the composite unipolar-bipolar semiconductor devices of the prior art do not in general provide new and desirable device characteristics and capabilities which are not available in simple combinations of interconnected field-effect transistors and binary junction transistors.
3. Related Art
The following U.S. Letters Patent contain information which is or might be held to be material to the examination of this patent application: 2,929,999; 3,112,411; 3,397,326; 3,401,319; 3,466,511; 3,649,843; 3,667,115; 3,865,649; 3,920,484; 4,016,596; 4,044,452; 4,143,392; and 4,237,472. No representation is made with respect to these patents other than that they are material or might be held to be material to the examination of this patent application. Particularly, no representation is made that any of these patents constitute prior art with respect to this patent application, or that a search has been made, or that no art more relevant than these patents exists. A copy of each of these patents was filed in the Patent and Trademark Office with this application.